A sequence d1≤⋯≤dn is graphical if it is the degree sequence of
a graph. Balister, the second author, Groenland, Johnston and Scott showed that
there are asymptotically C4n/n3/4 such sequences. However, the constant
C involves a probability that is only approximated. Using random walks and
limit theory for infinitely divisible probability distributions, we describe
C in terms of Walkup's formula for the number of rooted, unlabelled and
cyclically distinct plane trees